title: Influence of having a male twin on body mass index and risk for dyslipidemia in middle-aged and old women.
abstract: BACKGROUND
  Animal experiments suggest that exposure to elevated levels of androgens during development by means of so-called hormonal programming causes metabolic aberrations at adulthood. An indirect strategy to address the possible importance of such an influence also in humans would be to study female dizygotic twins, presuming that those with a twin brother--due to diffusion of testosterone--have been exposed to higher androgen levels prenatally.
  
  
  METHODS
  We have compared 8409 women with a male twin with 9166 women with a dizygotic female twin with respect to self-reported indices of anthropometry and metabolic aberrations at age 42 or older.
  
  
  RESULTS
  Body mass index (BMI), body weight and rate of dyslipidemia were moderately, but significantly, higher in women from opposite-sexed (OS) twin pairs; splitting for age revealed this difference to be present in those ≥ 60 years of age only.
  
  
  CONCLUSIONS
  The results (i) support the notion that comparisons of women with a twin brother with women from same-sexed twin pairs may be used to shed light on possible long-term effects of interindividual variations in early androgen exposure, and (ii) suggest that the effects of early androgen exposure on metabolism previously observed in animal experiments are of relevance also for humans.
authors.affiliation: Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Alexanderson
authors.forename: S
authors.initials: S
authors.lastname: Henningsson
authors.forename: P
authors.initials: P
authors.lastname: Lichtenstein
authors.forename: A
authors.initials: A
authors.lastname: Holmäng
authors.forename: E
authors.initials: E
authors.lastname: Eriksson
mesh_terms: D000328:Adult; D000368:Aged; D000728:Androgens / Q000235:genetics* / Q000378:metabolism; D015992:Body Mass Index; D001835:Body Weight; D015331:Cohort Studies; D050171:Dyslipidemias / Q000453:epidemiology / Q000209:etiology / Q000235:genetics* / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011944:Receptors, Androgen / Q000378:metabolism*; D018570:Risk Assessment; D012727:Sex Characteristics; D017678:Sex Distribution; D013548:Sweden / Q000453:epidemiology; D014429:Twins, Dizygotic
chemical_list: D000728:Androgens; D011944:Receptors, Androgen